This invention generally relates to a thrust bearing. More particularly, this invention relates to an active thrust bearing for a turbine engine.
Machinery such as generators and compressors that operate at relatively high speeds require low friction bearing assemblies that produce little heat. Hydraulic and air bearings are often utilized for such applications and provide the desired low friction. A conventional air bearing assembly includes a bearing element that contacts and supports a rotating member at rest. A cushion of air formed between the bearing element and the rotating member lifts the bearing elements off of the rotating member such that the rotating member is rotating and supported on the cushion of air. The cushion of air supporting the rotating element provides minimal friction, and therefore produces minimal heat.
Typically, the rotating member generates a thrust force that moves the rotating element from a desired position. Typically, the generator or compressor rotates at a fixed rotational speed such that the configuration of the air bearing can be designed to accommodate the thrust force and maintain the desired position of the rotating member. However, variations in thrust force that may result from operational mode changes or from changes in loading levels cannot be accommodated by the fixed configuration of the typical air bearing. Disadvantageously, such difficulties limit the use of air bearings to devices that operate at a fixed rotational speed and constant thrust force.
For this reason is it desirable to develop a low friction bearing system capable of adapting to variation in thrust forces generated by a rotating member.